MainActivity.java

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

  //in this you have to declare the functions
    private static final String TAG = "MainActivity" ;
    FloatingActionButton FabMainAdd, FabCamera, FabImportImage;
    Float translationY = 100f;

    OvershootInterpolator interpolator = new OvershootInterpolator();

    Boolean isMenuOpen = false;
//**End of Declaritions
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
      
      //init FAB menu
        iniFabMenu();

    }

    private void iniFabMenu() {
      
        //in this you need to refer FAB to xml icons 
        FabMainAdd = findViewById(R.id.main_add_fab);
        FabCamera = findViewById(R.id.camera_fab);
        FabImportImage = findViewById(R.id.import_image_fab);

      //in this the animation set Alpha to 0 float point as it should not appear in app start-up
        FabCamera.setAlpha(0f);
        FabImportImage.setAlpha(0f);
      
      //in this icons float down to-wards & out-wards main menu
        FabCamera.setTranslationY(translationY);
        FabImportImage.setTranslationY(translationY);
      
      //In this step adding on click listeners to each FAB
        FabMainAdd.setOnClickListener(this);
        FabCamera.setOnClickListener(this);
        FabImportImage.setOnClickListener(this);

    }

    private void openMenu() {
        isMenuOpen = !isMenuOpen;
      
      //in this step we added out-wards animation for all FABs
        FabMainAdd.animate().setInterpolator(interpolator).rotation(45f).setDuration(300).start();
        FabCamera.animate().translationY(0f).alpha(1f).setInterpolator(interpolator).setDuration(300).start();
        FabImportImage.animate().translationY(0f).alpha(1f).setInterpolator(interpolator).setDuration(300).start();

    }

    private void closeMenu() {
        isMenuOpen = !isMenuOpen;

      //in this step we added in-wards animation for all FABs
        FabMainAdd.animate().setInterpolator(interpolator).rotation(0f).setDuration(300).start();
        FabCamera.animate().translationY(translationY).alpha(0f).setInterpolator(interpolator).setDuration(300).start();
        FabImportImage.animate().translationY(translationY).alpha(0f).setInterpolator(interpolator).setDuration(300).start();

    }
  
    //This is used to know the process of button Handler using Debug-Log
    private void  handleCameraFab() {
        Log.i(TAG, "handleCameraFab: ");
    }

    @Override
    public void onClick(View view) {

      //In this step we added close and open menu for all floating buttons and also added Toast, Debug-Logs
      //using switch-case statements
        switch (view.getId()) {
            case R.id.main_add_fab:
                Log.i(TAG, "Select one of the menu");
                if (isMenuOpen) {
                    closeMenu();
                } else {
                    openMenu();
                    Toast.makeText(getApplicationContext(),"Select one of the menu",Toast.LENGTH_SHORT).show();
                }
                break;
            case R.id.camera_fab:
                Log.i(TAG, "Opening Camera.");
                handleCameraFab();
                if (isMenuOpen) {
                    closeMenu();
                } else {
                    openMenu();
                }
                Toast.makeText(getApplicationContext(),"Opening Camera.",Toast.LENGTH_SHORT).show();
                break;
            case R.id.import_image_fab:
                Log.i(TAG, "Opening Gallery..");
                handleCameraFab();
                if (isMenuOpen) {
                    closeMenu();
                } else {
                    openMenu();
                }
                Toast.makeText(getApplicationContext(),"Opening Gallery.",Toast.LENGTH_SHORT).show();
                break;
        }

    }
}